That 705 (as well as 660 and 670 yards) yard shot in my avatar was taken with my .223 AI loaded with 28 grains of H-335 and the 50 grain Nosler Ballistic Tip. Obviously, I am well pleased with this combo. I sorta thought that my first confirmed 500+ yard kills would be with my .220 Swift or maybe my .243, but it seems they were not needed. A good and accurate .223 Ackley Improved was all it took for me.
Just built two 223 ackley ar's, one heavy and one light, with 1-12 twist barrels. They both like 28.5 grains A2230 and 40 gr bullets. One likes vmax and one likes nbt's. H335 also worked very well, but I have more 2230 on hand right now.
While H335 seems to be the most popular powder I tried it in my 223AI and it performed poorly. Benchmark did good but H4895 did even better.
I had Krieger make, chamber and install the barrel. I tried some of the loads given me by former members here and I started showing signs of high pressure without achieving the velocities others were getting when using H335. I get good accuracy and get very close to the high velocities others are getting.
I used H-335 on my 40 grain vmax and AA-2520 for the 50 grainers for years until I tried VV-133 for the 40 grain and VV-135 for the 50 grainers.The kind of accuracy that people think you are BSing about and great velocity